Reliable and affordable prescription drug coverage is important to nursing home residents who require many medications to manage multiple co-morbid conditions. Yet, the Medicare Part D (Part D) drug program is difficult to join due complex enrollment requirements. Nursing home residents have significant cognitive, functional, and sensory deficits that make Part D enrollment especially challenging. The objectives of this study are to describe the current landscape of drug coverage in the nursing home setting, identify factors that influence Part D enrollment, and estimate how drug coverage influences the use of medications. A unique aspect of this study is to follow a group of residents who are automatically enrolled into Part D due to Medicaid program rules, and to compare before and after changes in their medication use. We will also examine changes in important health outcomes such as hospitalizations that are avoidable and death. To complete these objectives, this research project will analyze data collected from a large long-term care pharmacy, nursing home resident care plans, the Medicare program and nursing home surveys. Additionally, this project will conduct an internet-based consensus panel of experts to develop a new tool of medication underuse. This project should be in a unique position to inform the Medicare program and policymakers about the experience of nursing home residents under the current Part D enrollment requirements and how to create more equitable access to this vital benefit of the Medicare program.